Metal finishing is an essential process for producing strong, high-quality metallic products. This is especially true for specialized metal parts that require specific chemical, electrical, or tarnish resistances. There are also many types of metal finishes, which can impact material hardness, workflow speeds, production costs, and more.
With so many variables, it can be tough to find the right finishes for your unique metalworking projects, let alone achieve them. So today, let’s review four of the most common (and practical) types of metal finishes—as well as how to produce them consistently and cost-efficiently across your metalworking process.
1. Directional Metal Finishes
Directional metal finishes (also known as brushed or architectural finishes) are characterized by fine and uniform polishing grit lines along the length of the workpiece. This glossy, high-sheen finish provides a distinct and attractive aesthetic—while removing any edges and surface flaws. Directional finishes are typically used for stainless steel products, particularly in architectural, transportation, and home applications.
How They’re Made
Directional metal finishes can be achieved by polishing metal workpieces with a 120-180 grit belt—then softening the finish with an 80-120 grit abrasive belt or pad. The most efficient way to create directional finishes is by using a wet metal polishing and finishing machine. These powerful tools can be customized with different head counts, head types, and abrasive belt lengths to create an optimal directional finish across your metal parts.
2. Non-Directional Metal Finishes
Non-directional metal finishes are characterized by a consistent, non-directional pattern across the workpiece. These finishes are typically used to polish metal parts in preparation for additional surface treatment, such as paint. Because non-directional finishes lack a distinguished pattern, they’re also useful for concealing scratches and blemishes across high-contact areas.
How They’re Made
Non-directional metal finishes are often created using orbital sanders with fine, medium, or coarse-grade sanding discs. Automatic metal finishing machines are also highly recommended for creating non-directional metal finishes—and can often finish both sides of a workpiece in a single pass.
3. Mill Finishes
Mill finishes (also known as matte finishes) are characterized by a smooth, dull surface texture. These are some of the least expensive finishing options and are often applied when a part’s aesthetic appearance is unimportant. Mill finishes can also be applied to smooth a part in preparation for further finishing or processing—and are commonly used across stainless steel products, including components for refrigeration, sewage, and dry cleaning equipment.
How They’re Made
Mill metal finishes can be created by processing parts through a rolling mill or drawing process. Specialized dies and rolls remove pitting and roughness from the workpiece, achieving a smooth finish that can then be treated via polishing, industrial etching, or other surface processing.
4. Mirror-Polish Finishes
Mirror-polish finishes are characterized by a highly polished and reflective “mirror-like” look. This finish is aesthetically pleasing and removes any crevices or imperfections that may contain harmful particles—enhancing the metal’s resistance to corrosive damage. The consistency, strength, and blemish-free look of mirror-polish finishes make them popular across various markets and metalworking applications.
How They’re Made
Mirror-polish finishes are difficult and labor-intensive to create by hand, namely because they require specific grinding and polishing techniques. The more efficient route is to use a wet or dry metal finishing machine, which can automatically apply abrasives to achieve the intended finish—both quickly and consistently.
The Impact of Metal Finishing Machines
No matter which types of metal finishes customers request, it’s crucial to deliver a consistent end product that aligns with their technical and aesthetic requirements. That’s why we recommend investing in metal finishing equipment. These automated solutions can be outfitted with different parts and configurations to match precise tolerances, measurements, and finish types—more quickly and consistently compared to manual tools.
A few key advantages of metal finishing machines include:
Consistency: Metal finishing machines can process both sides of a workpiece evenly in a single pass, increasing the quality and consistency of any desired finish.
Cost-Efficiency: Automated machines can quickly and accurately finish almost any kind of metal part, ensuring more cost-efficient production without sacrificing quality.
Workplace Safety: Metal finishing machines use conveyor belts and rolls to safely process parts, creating safer workflows compared to hand polishing and finishing—and reducing the risk of cuts and hand strain.
Finishing and polishing metals can be accomplished using either a dry or wet process. However, the wet process delivers the best results when finishing most types of metal materials. For example, our 1000 Series Wet Metal Machines can be equipped with a range of abrasive solutions and heads for metal deburring and finishing. We also offer flexible equipment financing options to ensure you get the right metal finishing machine without breaking your budget.
Achieve the Perfect Finish With Apex Machine Group
Ready to learn more about metal finishing and the different tools you can use to make this process easier? Then connect with the Apex team today. Our specialists can walk you through the different types of metal finishes—and help you choose the best equipment and processes for your customer’s unique requirements.